1.1
What is cloud computing & benefits
Define cloud computing, map core AWS service examples, and explain pay-as-you-go, elasticity, scalability, availability, fault tolerance, and agility.
Key points
- Cloud = on-demand computing resources over a network.
- EC2, S3, RDS, VPC, and Lambda illustrate major service categories.
- Elasticity adjusts capacity automatically; scalability is capacity growth (vertical vs horizontal).
- High availability uses redundancy; fault tolerance survives component failure.
What is cloud computing?
Cloud computing means using computing resources over a network on an on-demand basis.
Core AWS examples
- Compute → Amazon EC2
- Storage → Amazon S3
- Database → Amazon RDS
- Networking → Amazon VPC
- Serverless compute → AWS Lambda
In a traditional data center, a company must purchase, provision, and maintain physical servers. With AWS, infrastructure can be provisioned according to demand.
Benefits of AWS Cloud
Pay-as-you-go
You generally pay according to the AWS resources and services you use.
Elasticity
Resources can automatically increase when demand increases and decrease when demand falls.
Example
An e-commerce website experiences increased traffic during a festival. Additional compute capacity can be added to handle the increased demand.
Scalability
Scalability is the ability to increase or decrease a system's capacity.
- Vertical scaling → Increase the capacity of an existing instance.
- Horizontal scaling → Add more instances.
High availability
High availability means designing systems to remain accessible by using redundancy and multiple resources or Availability Zones.
Fault tolerance
Fault tolerance means a system can continue operating even when a component fails.
Agility
AWS allows organizations to create, modify, and deploy infrastructure quickly.
Exam focus
Scenario questions often contrast traditional data centers with on-demand elasticity and agility.